The virqfd functionality that is used by VFIO_PCI to implement interrupt
masking and unmasking via an eventfd, is generic enough and can be reused
by another driver. Move it to a separate file in order to allow the code
to be shared.
Also properly export virqfd_enable and virqfd_disable in the process.
Signed-off-by: Antonios Motakis <[email protected]>
---
drivers/vfio/Makefile | 4 +-
drivers/vfio/pci/vfio_pci_intrs.c | 213 -----------------------------------
drivers/vfio/pci/vfio_pci_private.h | 3 -
drivers/vfio/virqfd.c | 214 ++++++++++++++++++++++++++++++++++++
include/linux/vfio.h | 28 +++++
5 files changed, 245 insertions(+), 217 deletions(-)
create mode 100644 drivers/vfio/virqfd.c
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index dadf0ca..d798b09 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -1,4 +1,6 @@
-obj-$(CONFIG_VFIO) += vfio.o
+vfio_core-y := vfio.o virqfd.o
+
+obj-$(CONFIG_VFIO) += vfio_core.o
obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 9dd49c9..3f909bb 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -18,226 +18,13 @@
#include <linux/eventfd.h>
#include <linux/pci.h>
#include <linux/file.h>
-#include <linux/poll.h>
#include <linux/vfio.h>
#include <linux/wait.h>
-#include <linux/workqueue.h>
#include <linux/slab.h>
#include "vfio_pci_private.h"
/*
- * IRQfd - generic
- */
-struct virqfd {
- struct vfio_pci_device *vdev;
- struct eventfd_ctx *eventfd;
- int (*handler)(struct vfio_pci_device *, void *);
- void (*thread)(struct vfio_pci_device *, void *);
- void *data;
- struct work_struct inject;
- wait_queue_t wait;
- poll_table pt;
- struct work_struct shutdown;
- struct virqfd **pvirqfd;
-};
-
-static struct workqueue_struct *vfio_irqfd_cleanup_wq;
-
-int __init vfio_pci_virqfd_init(void)
-{
- vfio_irqfd_cleanup_wq =
- create_singlethread_workqueue("vfio-irqfd-cleanup");
- if (!vfio_irqfd_cleanup_wq)
- return -ENOMEM;
-
- return 0;
-}
-
-void vfio_pci_virqfd_exit(void)
-{
- destroy_workqueue(vfio_irqfd_cleanup_wq);
-}
-
-static void virqfd_deactivate(struct virqfd *virqfd)
-{
- queue_work(vfio_irqfd_cleanup_wq, &virqfd->shutdown);
-}
-
-static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
-{
- struct virqfd *virqfd = container_of(wait, struct virqfd, wait);
- unsigned long flags = (unsigned long)key;
-
- if (flags & POLLIN) {
- /* An event has been signaled, call function */
- if ((!virqfd->handler ||
- virqfd->handler(virqfd->vdev, virqfd->data)) &&
- virqfd->thread)
- schedule_work(&virqfd->inject);
- }
-
- if (flags & POLLHUP) {
- unsigned long flags;
- spin_lock_irqsave(&virqfd->vdev->irqlock, flags);
-
- /*
- * The eventfd is closing, if the virqfd has not yet been
- * queued for release, as determined by testing whether the
- * vdev pointer to it is still valid, queue it now. As
- * with kvm irqfds, we know we won't race against the virqfd
- * going away because we hold wqh->lock to get here.
- */
- if (*(virqfd->pvirqfd) == virqfd) {
- *(virqfd->pvirqfd) = NULL;
- virqfd_deactivate(virqfd);
- }
-
- spin_unlock_irqrestore(&virqfd->vdev->irqlock, flags);
- }
-
- return 0;
-}
-
-static void virqfd_ptable_queue_proc(struct file *file,
- wait_queue_head_t *wqh, poll_table *pt)
-{
- struct virqfd *virqfd = container_of(pt, struct virqfd, pt);
- add_wait_queue(wqh, &virqfd->wait);
-}
-
-static void virqfd_shutdown(struct work_struct *work)
-{
- struct virqfd *virqfd = container_of(work, struct virqfd, shutdown);
- u64 cnt;
-
- eventfd_ctx_remove_wait_queue(virqfd->eventfd, &virqfd->wait, &cnt);
- flush_work(&virqfd->inject);
- eventfd_ctx_put(virqfd->eventfd);
-
- kfree(virqfd);
-}
-
-static void virqfd_inject(struct work_struct *work)
-{
- struct virqfd *virqfd = container_of(work, struct virqfd, inject);
- if (virqfd->thread)
- virqfd->thread(virqfd->vdev, virqfd->data);
-}
-
-static int virqfd_enable(struct vfio_pci_device *vdev,
- int (*handler)(struct vfio_pci_device *, void *),
- void (*thread)(struct vfio_pci_device *, void *),
- void *data, struct virqfd **pvirqfd, int fd)
-{
- struct fd irqfd;
- struct eventfd_ctx *ctx;
- struct virqfd *virqfd;
- int ret = 0;
- unsigned int events;
-
- virqfd = kzalloc(sizeof(*virqfd), GFP_KERNEL);
- if (!virqfd)
- return -ENOMEM;
-
- virqfd->pvirqfd = pvirqfd;
- virqfd->vdev = vdev;
- virqfd->handler = handler;
- virqfd->thread = thread;
- virqfd->data = data;
-
- INIT_WORK(&virqfd->shutdown, virqfd_shutdown);
- INIT_WORK(&virqfd->inject, virqfd_inject);
-
- irqfd = fdget(fd);
- if (!irqfd.file) {
- ret = -EBADF;
- goto err_fd;
- }
-
- ctx = eventfd_ctx_fileget(irqfd.file);
- if (IS_ERR(ctx)) {
- ret = PTR_ERR(ctx);
- goto err_ctx;
- }
-
- virqfd->eventfd = ctx;
-
- /*
- * virqfds can be released by closing the eventfd or directly
- * through ioctl. These are both done through a workqueue, so
- * we update the pointer to the virqfd under lock to avoid
- * pushing multiple jobs to release the same virqfd.
- */
- spin_lock_irq(&vdev->irqlock);
-
- if (*pvirqfd) {
- spin_unlock_irq(&vdev->irqlock);
- ret = -EBUSY;
- goto err_busy;
- }
- *pvirqfd = virqfd;
-
- spin_unlock_irq(&vdev->irqlock);
-
- /*
- * Install our own custom wake-up handling so we are notified via
- * a callback whenever someone signals the underlying eventfd.
- */
- init_waitqueue_func_entry(&virqfd->wait, virqfd_wakeup);
- init_poll_funcptr(&virqfd->pt, virqfd_ptable_queue_proc);
-
- events = irqfd.file->f_op->poll(irqfd.file, &virqfd->pt);
-
- /*
- * Check if there was an event already pending on the eventfd
- * before we registered and trigger it as if we didn't miss it.
- */
- if (events & POLLIN) {
- if ((!handler || handler(vdev, data)) && thread)
- schedule_work(&virqfd->inject);
- }
-
- /*
- * Do not drop the file until the irqfd is fully initialized,
- * otherwise we might race against the POLLHUP.
- */
- fdput(irqfd);
-
- return 0;
-err_busy:
- eventfd_ctx_put(ctx);
-err_ctx:
- fdput(irqfd);
-err_fd:
- kfree(virqfd);
-
- return ret;
-}
-
-static void virqfd_disable(struct vfio_pci_device *vdev,
- struct virqfd **pvirqfd)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&vdev->irqlock, flags);
-
- if (*pvirqfd) {
- virqfd_deactivate(*pvirqfd);
- *pvirqfd = NULL;
- }
-
- spin_unlock_irqrestore(&vdev->irqlock, flags);
-
- /*
- * Block until we know all outstanding shutdown jobs have completed.
- * Even if we don't queue the job, flush the wq to be sure it's
- * been released.
- */
- flush_workqueue(vfio_irqfd_cleanup_wq);
-}
-
-/*
* INTx
*/
static void vfio_send_intx_eventfd(struct vfio_pci_device *vdev, void *unused)
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 671c17a..4c89e0e 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -86,9 +86,6 @@ extern ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
extern int vfio_pci_init_perm_bits(void);
extern void vfio_pci_uninit_perm_bits(void);
-extern int vfio_pci_virqfd_init(void);
-extern void vfio_pci_virqfd_exit(void);
-
extern int vfio_config_init(struct vfio_pci_device *vdev);
extern void vfio_config_free(struct vfio_pci_device *vdev);
#endif /* VFIO_PCI_PRIVATE_H */
diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c
new file mode 100644
index 0000000..243eb61
--- /dev/null
+++ b/drivers/vfio/virqfd.c
@@ -0,0 +1,214 @@
+/*
+ * VFIO generic eventfd code for IRQFD support.
+ * Derived from drivers/vfio/pci/vfio_pci_intrs.c
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
+ * Author: Alex Williamson <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/vfio.h>
+#include <linux/eventfd.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include "pci/vfio_pci_private.h"
+
+static struct workqueue_struct *vfio_irqfd_cleanup_wq;
+
+int __init vfio_pci_virqfd_init(void)
+{
+ vfio_irqfd_cleanup_wq =
+ create_singlethread_workqueue("vfio-irqfd-cleanup");
+ if (!vfio_irqfd_cleanup_wq)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void vfio_pci_virqfd_exit(void)
+{
+ destroy_workqueue(vfio_irqfd_cleanup_wq);
+}
+
+static void virqfd_deactivate(struct virqfd *virqfd)
+{
+ queue_work(vfio_irqfd_cleanup_wq, &virqfd->shutdown);
+}
+
+static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+ struct virqfd *virqfd = container_of(wait, struct virqfd, wait);
+ unsigned long flags = (unsigned long)key;
+
+ if (flags & POLLIN) {
+ /* An event has been signaled, call function */
+ if ((!virqfd->handler ||
+ virqfd->handler(virqfd->vdev, virqfd->data)) &&
+ virqfd->thread)
+ schedule_work(&virqfd->inject);
+ }
+
+ if (flags & POLLHUP) {
+ unsigned long flags;
+ spin_lock_irqsave(&virqfd->vdev->irqlock, flags);
+
+ /*
+ * The eventfd is closing, if the virqfd has not yet been
+ * queued for release, as determined by testing whether the
+ * vdev pointer to it is still valid, queue it now. As
+ * with kvm irqfds, we know we won't race against the virqfd
+ * going away because we hold wqh->lock to get here.
+ */
+ if (*(virqfd->pvirqfd) == virqfd) {
+ *(virqfd->pvirqfd) = NULL;
+ virqfd_deactivate(virqfd);
+ }
+
+ spin_unlock_irqrestore(&virqfd->vdev->irqlock, flags);
+ }
+
+ return 0;
+}
+
+static void virqfd_ptable_queue_proc(struct file *file,
+ wait_queue_head_t *wqh, poll_table *pt)
+{
+ struct virqfd *virqfd = container_of(pt, struct virqfd, pt);
+ add_wait_queue(wqh, &virqfd->wait);
+}
+
+static void virqfd_shutdown(struct work_struct *work)
+{
+ struct virqfd *virqfd = container_of(work, struct virqfd, shutdown);
+ u64 cnt;
+
+ eventfd_ctx_remove_wait_queue(virqfd->eventfd, &virqfd->wait, &cnt);
+ flush_work(&virqfd->inject);
+ eventfd_ctx_put(virqfd->eventfd);
+
+ kfree(virqfd);
+}
+
+static void virqfd_inject(struct work_struct *work)
+{
+ struct virqfd *virqfd = container_of(work, struct virqfd, inject);
+ if (virqfd->thread)
+ virqfd->thread(virqfd->vdev, virqfd->data);
+}
+
+int virqfd_enable(struct vfio_pci_device *vdev,
+ int (*handler)(struct vfio_pci_device *, void *),
+ void (*thread)(struct vfio_pci_device *, void *),
+ void *data, struct virqfd **pvirqfd, int fd)
+{
+ struct fd irqfd;
+ struct eventfd_ctx *ctx;
+ struct virqfd *virqfd;
+ int ret = 0;
+ unsigned int events;
+
+ virqfd = kzalloc(sizeof(*virqfd), GFP_KERNEL);
+ if (!virqfd)
+ return -ENOMEM;
+
+ virqfd->pvirqfd = pvirqfd;
+ virqfd->vdev = vdev;
+ virqfd->handler = handler;
+ virqfd->thread = thread;
+ virqfd->data = data;
+
+ INIT_WORK(&virqfd->shutdown, virqfd_shutdown);
+ INIT_WORK(&virqfd->inject, virqfd_inject);
+
+ irqfd = fdget(fd);
+ if (!irqfd.file) {
+ ret = -EBADF;
+ goto err_fd;
+ }
+
+ ctx = eventfd_ctx_fileget(irqfd.file);
+ if (IS_ERR(ctx)) {
+ ret = PTR_ERR(ctx);
+ goto err_ctx;
+ }
+
+ virqfd->eventfd = ctx;
+
+ /*
+ * virqfds can be released by closing the eventfd or directly
+ * through ioctl. These are both done through a workqueue, so
+ * we update the pointer to the virqfd under lock to avoid
+ * pushing multiple jobs to release the same virqfd.
+ */
+ spin_lock_irq(&vdev->irqlock);
+
+ if (*pvirqfd) {
+ spin_unlock_irq(&vdev->irqlock);
+ ret = -EBUSY;
+ goto err_busy;
+ }
+ *pvirqfd = virqfd;
+
+ spin_unlock_irq(&vdev->irqlock);
+
+ /*
+ * Install our own custom wake-up handling so we are notified via
+ * a callback whenever someone signals the underlying eventfd.
+ */
+ init_waitqueue_func_entry(&virqfd->wait, virqfd_wakeup);
+ init_poll_funcptr(&virqfd->pt, virqfd_ptable_queue_proc);
+
+ events = irqfd.file->f_op->poll(irqfd.file, &virqfd->pt);
+
+ /*
+ * Check if there was an event already pending on the eventfd
+ * before we registered and trigger it as if we didn't miss it.
+ */
+ if (events & POLLIN) {
+ if ((!handler || handler(vdev, data)) && thread)
+ schedule_work(&virqfd->inject);
+ }
+
+ /*
+ * Do not drop the file until the irqfd is fully initialized,
+ * otherwise we might race against the POLLHUP.
+ */
+ fdput(irqfd);
+
+ return 0;
+err_busy:
+ eventfd_ctx_put(ctx);
+err_ctx:
+ fdput(irqfd);
+err_fd:
+ kfree(virqfd);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(virqfd_enable);
+
+void virqfd_disable(struct vfio_pci_device *vdev,
+ struct virqfd **pvirqfd)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&vdev->irqlock, flags);
+
+ if (*pvirqfd) {
+ virqfd_deactivate(*pvirqfd);
+ *pvirqfd = NULL;
+ }
+
+ spin_unlock_irqrestore(&vdev->irqlock, flags);
+
+ /*
+ * Block until we know all outstanding shutdown jobs have completed.
+ * Even if we don't queue the job, flush the wq to be sure it's
+ * been released.
+ */
+ flush_workqueue(vfio_irqfd_cleanup_wq);
+}
+EXPORT_SYMBOL_GPL(virqfd_disable);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index d320411..a077c48 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -14,6 +14,8 @@
#include <linux/iommu.h>
#include <linux/mm.h>
+#include <linux/workqueue.h>
+#include <linux/poll.h>
#include <uapi/linux/vfio.h>
/**
@@ -121,4 +123,30 @@ static inline long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
return -ENOTTY;
}
#endif /* CONFIG_EEH */
+
+/*
+ * IRQFD support
+ */
+struct virqfd {
+ struct vfio_pci_device *vdev;
+ struct eventfd_ctx *eventfd;
+ int (*handler)(struct vfio_pci_device *, void *);
+ void (*thread)(struct vfio_pci_device *, void *);
+ void *data;
+ struct work_struct inject;
+ wait_queue_t wait;
+ poll_table pt;
+ struct work_struct shutdown;
+ struct virqfd **pvirqfd;
+};
+
+extern int vfio_pci_virqfd_init(void);
+extern void vfio_pci_virqfd_exit(void);
+extern int virqfd_enable(struct vfio_pci_device *vdev,
+ int (*handler)(struct vfio_pci_device *, void *),
+ void (*thread)(struct vfio_pci_device *, void *),
+ void *data, struct virqfd **pvirqfd, int fd);
+extern void virqfd_disable(struct vfio_pci_device *vdev,
+ struct virqfd **pvirqfd);
+
#endif /* VFIO_H */
--
2.1.1
Hi Antonios,
On Mon, Oct 27, 2014 at 12:07 PM, Antonios Motakis
<[email protected]> wrote:
> The virqfd functionality that is used by VFIO_PCI to implement interrupt
> masking and unmasking via an eventfd, is generic enough and can be reused
> by another driver. Move it to a separate file in order to allow the code
> to be shared.
>
> Also properly export virqfd_enable and virqfd_disable in the process.
Alex will handle this, not me, but my personal preference is to avoid
doing things "in the process" because the small changes get lost in
the big patch.
I'd rather see a strict move that changes no code at all (except
things like necessary Makefile changes), followed by a smaller patch
that does the additional stuff.
Does "properly export" mean that those functions were previously
*improperly* exported and the way they used to be exported caused a
problem? Or does it just mean "export"?
Bjorn
> Signed-off-by: Antonios Motakis <[email protected]>
> ---
> drivers/vfio/Makefile | 4 +-
> drivers/vfio/pci/vfio_pci_intrs.c | 213 -----------------------------------
> drivers/vfio/pci/vfio_pci_private.h | 3 -
> drivers/vfio/virqfd.c | 214 ++++++++++++++++++++++++++++++++++++
> include/linux/vfio.h | 28 +++++
> 5 files changed, 245 insertions(+), 217 deletions(-)
> create mode 100644 drivers/vfio/virqfd.c
On Mon, Oct 27, 2014 at 8:16 PM, Bjorn Helgaas <[email protected]> wrote:
> Hi Antonios,
>
> On Mon, Oct 27, 2014 at 12:07 PM, Antonios Motakis
> <[email protected]> wrote:
>> The virqfd functionality that is used by VFIO_PCI to implement interrupt
>> masking and unmasking via an eventfd, is generic enough and can be reused
>> by another driver. Move it to a separate file in order to allow the code
>> to be shared.
>>
>> Also properly export virqfd_enable and virqfd_disable in the process.
>
> Alex will handle this, not me, but my personal preference is to avoid
> doing things "in the process" because the small changes get lost in
> the big patch.
>
> I'd rather see a strict move that changes no code at all (except
> things like necessary Makefile changes), followed by a smaller patch
> that does the additional stuff.
>
> Does "properly export" mean that those functions were previously
> *improperly* exported and the way they used to be exported caused a
> problem? Or does it just mean "export"?
It just means "export", but you are right there is no reason why to
export it in this patch. I will move it to one of the next patches.
>
> Bjorn
>
>> Signed-off-by: Antonios Motakis <[email protected]>
>> ---
>> drivers/vfio/Makefile | 4 +-
>> drivers/vfio/pci/vfio_pci_intrs.c | 213 -----------------------------------
>> drivers/vfio/pci/vfio_pci_private.h | 3 -
>> drivers/vfio/virqfd.c | 214 ++++++++++++++++++++++++++++++++++++
>> include/linux/vfio.h | 28 +++++
>> 5 files changed, 245 insertions(+), 217 deletions(-)
>> create mode 100644 drivers/vfio/virqfd.c